Supplementation of PQQ from pregnancy prevents MK-801-induced schizophrenia-like behaviors in mice.

RATIONALE: At present, the research on the prevention of schizophrenia is still in its infancy. Pyrroloquinoline quinone (PQQ) has potential to treat psychological and neurological diseases including schizophrenia. However, the preventive effect of PQQ on schizophrenia remains unclear. OBJECTIVES: In this study, we aimed to examine the preventive effect of supplementation of dietary PQQ from pregnancy or after birth on dizocilpine (MK-801)-induced schizophrenia-like behaviors in mice. RESULTS: Supplementation of dietary PQQ from pregnancy could effectively prevent MK-801-induced weight gain decrease, hyperlocomotion, stereotypical behavior, ataxia, exploratory activity decrease, social interaction disorder, memory deficit, and depression in mice. Supplementation of dietary PQQ after birth could effectively prevent MK-801-induced weight gain decrease, stereotypical behavior, ataxia, and memory deficit in mice. Female mice responded to a greater degree than males in preventing MK-801-induced weight gain decrease in both forms of PQQ supplementation. For mice that began PQQ supplementation after birth, females performed better than males in preventing MK-801-induced ataxia, memory deficit, and depression. For mice that began PQQ supplementation from pregnancy, males performed better than females in preventing MK-801-induced memory deficit. In vitro experiments indicated that PQQ supplementation in the earlier stage of life contributed to the growth of neurons and the development of neurites. CONCLUSIONS: Our current study suggested that PQQ supplementation from pregnancy or postpartum could prevent some schizophrenia-like behaviors induced by MK-801 in mice. Our work supported the potential usage of dietary supplement of PQQ in preventing or alleviating symptoms associated with schizophrenia.

Efficacy of gecko polysaccharide on suppressed immune response induced by cyclophosphamide in mice.

OBJECTIVE: To evaluate the efficacy of gecko polysaccharide on the cyclophosphamide-induced suppressed immune response in mice. METHODS: Polysaccharides were extracted from fresh gecko for the first time using an orthogonal method and protein was removed using Sevag reagent (chloroform:N-butanol, 5:1, v/v). The gecko polysaccharide (GPCE) content was determined by the phenol-concentrated sulfuric acid method. An immunocompromised mouse model was established by intraperitoneally injecting cyclophosphamide at 100 mg/kg into 48 mice. The effects of GPCE on immune regulation in mice were assessed by a thymus-spleen index, serum hemolysin levels, and the proliferation of splenic lymphocytes. Spleen cell CD4+, CD8+, and the CD4+/CD8+ ratio were evaluated by flow cytometry and the tumor necrosis factor-α (TNF-α) levels were measured by ELISA. RESULTS: The optimal extraction process for gecko polysaccharide included a 1:20 ratio of material to liquid (v/v), an extraction temperature of 60 ℃ and a time of 2 h. The polysaccharide content of the extract was 65.74%. GPCE was analyzed by HPLC and primarily contained glucose and small amounts of mannose, rha, and gal. Compared with the model, the thymus index, the spleen index were indices for GPCE increased with dose, whereas the high and medium groups exhibited significant differences (P < 0.05, P < 0.01). Higher doses of GPCE increased serum TNF-α levels and there was a significant difference between the medium and high GPCE doses and the model (P < 0.05, P < 0.01); The number of CD4+ cells and the CD4+/CD8+ ratio in the gecko polysaccharide group were increased (P < 0.05) and there was no statistical difference in the number of CD8+ cells in the gecko polysaccharide group (P > 0.05); The high GPCE dose significantly increased the level of serum hemolysin (P < 0.01). CONCLUSIONS: Gecko polysaccharide significantly improved the suppressed immune response induced by cyclophosphamide in mice and promoted the secretion of tumor necrosis factor. The mechanism of gecko polysaccharide as an antitumor agent warrants further study.

PQQ ameliorates D-galactose induced cognitive impairments by reducing glutamate neurotoxicity via the GSK-3ß/Akt signaling pathway in mouse.

Oxidative stress is known to be associated with various age-related diseases. D-galactose (D-gal) has been considered a senescent model which induces oxidative stress response resulting in memory dysfunction. Pyrroloquinoline quinone (PQQ) is a redox cofactor which is found in various foods. In our previous study, we found that PQQ may be converted into a derivative by binding with amino acid, which is beneficial to several pathological processes. In this study, we found a beneficial glutamate mixture which may diminish neurotoxicity by oxidative stress in D-gal induced mouse. Our results showed that PQQ may influence the generation of proinflammatory mediators, including cytokines and prostaglandins during aging process. D-gal-induced mouse showed increased MDA and ROS levels, and decreased T-AOC activities in the hippocampus, these changes were reversed by PQQ supplementation. Furthermore, PQQ statistically enhanced Superoxide Dismutase SOD2 mRNA expression. PQQ could ameliorate the memory deficits and neurotoxicity induced by D-gal via binding with excess glutamate, which provide a link between glutamate-mediated neurotoxicity, inflammation and oxidative stress. In addition, PQQ reduced the up-regulated expression of p-Akt by D-gal and maintained the activity of GSK-3ß, resulting in a down-regulation of p-Tau level in hippocampus. PQQ modulated memory ability partly via Akt/GSK-3ß pathway.